Automatic urine disposal device and urine receptacle used therefor

ABSTRACT

In a urine receptacle of an automatic urine disposal device, a urine backflow prevention sheet, with no water permeability, and having funnel-shaped pores, is placed between a top sheet and a urine absorbing sheet. A pair of rectangular electrodes, constituting a urine detection sensor, is glued onto an electrode support sheet and is placed between the top sheet and the urine backflow prevention sheet. A plurality of funnel-shaped pores is formed on the urine backflow prevention sheet.

The present application claims priority from Japanese application JP2003-340488, filed on Sep. 30, 2003, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

The present invention relates to an automatic urine disposal device and a urine receptacle of the type worn by the elderly, people with difficulty walking, hospitalized patients, physically disabled people, and others who are unable to voluntarily control their bladder or to clean up urine on their own.

In general, the elderly, physically disabled people, and those who are hospitalized due to injuries or illness sometimes become unable to voluntarily control their bladder or clean up urine on their own. In those situations, generally, a catheter is directly inserted into the bladder to discharge urine, or a paper diaper is used.

When a catheter is directly inserted into the bladder, the wearer feels great discomfort, and there is also the probability of injuring the urethra or bladder or the occurrence of an infection. Thus, expertise in the insertion of the catheter, as well as the use of special sterilized utensils, is required.

Prolonged use of a paper diaper may cause urine leakage, a feeling of discomfort, dampness inside the diaper, or skin troubles, such as rashes. To avoid this, the paper diaper must be frequently changed, which will impose considerable physical and mental burdens on both the wearer and the caretaker. Imposed on a daily basis, those physical and mental burdens become a big concern and a significant economic burden as well.

In order to solve the problems listed above, an automatic urine disposal device, which uses a urine receptacle and a vacuum pump to suction urine and then to direct the urine into a urine tank via a urine drainage tube, has been developed. A urine detection sensor for detecting urination and activating the vacuum pump is used in such an automatic urine disposal device. As for the urine detection sensor, there are various methods available for urine detection, such as: detection based on the electrical conduction of a pair of electrodes as a result of urination; detection based on changes in pressure inside the urine drainage tube as a result of urination; and detection based on detection of odor components in excretory substances. Detection based on changes in pressure inside the urine drainage tube as a result of urination and detection based on detection of odor components in excretory substances will make the device complicated and thus expensive. Therefore, for practical use, urine detection based on the electrical conduction of a pair of electrodes has been considered effective.

Automatic urine disposal devices with a urine detection sensor which was a pair of electrodes have been disclosed in Japanese Application Patent Laid-open Publications No. Hei 07-171182 and No. Hei 10-85275.

The urine receptacle of an automatic urine disposal device has a urine absorbing sheet below a top sheet made of a nonwoven fabric which allows urine to easily pass therethrough. A pair of electrodes, constituting a urine detection sensor, is located between this top sheet and a urine absorbing sheet. Below the urine absorbing sheet, a urine absorbing space forming material for defining a urine flow path is provided in order to collect urine from a large area. Sometimes the urine absorbing sheet or the urine absorbing space forming material fails to collect urine and the urine there remains uncollected. This may cause the uncollected urine to ooze toward the urine detection sensor when the wearer changes his/her posture or when his/her weight is shifted.

The urine detection sensor with a pair of electrodes becomes electrically conductive due to the residual urine oozing out, detects the presence of urine, and activates the vacuum pump. If the vacuum pump becomes activated in this manner when the wearer is not urinating, the wearer feels discomfort, thus creating a problem in that he/she cannot use it comfortably.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to provide an automatic urine disposal device in which it is possible to prevent improper operation of a vacuum pump caused by residual urine even though a urine detection sensor with a pair of electrodes is used, and also to provide a urine receptacle to be used with such an automatic urine disposal device.

The present invention is characterized in that: a urine backflow prevention sheet having no water permeability, with funnel-shaped pores, is placed between a top sheet and a urine absorbing sheet; and a pair of electrodes constituting a urine detection sensor is placed between the top sheet and the urine backflow prevention sheet. A plurality of funnel-shaped pores are formed on the urine backflow prevention sheet.

In accordance with the present invention, the urine detection sensor is placed on the urine backflow prevention sheet (on the top sheet side) which has a plurality of funnel-shaped pores. Discharged urine can easily flow from the top sheet to a urine absorbing sheet, since each funnel-shaped pore has a large opening area to accommodate flow in that direction, and discharged urine cannot backflow easily, since each funnel-shaped pore has a small opening area for fluid flow in the reverse direction. This is because the urine on the urine absorbed sheet has a surface tension.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view showing a first embodiment of an automatic urine disposal device of the present invention;

FIG. 2 is an exploded perspective view of the device of FIG. 1 with its urine tank partially removed and its lid case removed;

FIG. 3 is an exploded perspective view of a urine receptacle; and

FIG. 4 is a cross-sectional view of the urine receptacle taken along the line A-A in FIG. 3;

FIG. 5 is a partially enlarged view of a urine backflow prevention sheet;

FIG. 6 is a perspective view of a urine detection sensor;

FIG. 7 is a perspective view of the urine detection sensor of another embodiment of the present invention;

FIG. 8 is a perspective view of the urine detection sensor of another embodiment of the present invention; and

FIG. 9 is a perspective view of the urine detection sensor of another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A urine receptacle for absorbing urine is placed in contact with the urinating part of a device wearer. After being absorbed by the urine receiver, urine is directed into a sealed urine tank via a urine drainage tube. In the urine tank, a urine swaying motion control means is provided to control swaying movement or rippling motions of the discharged urine. A vacuum pump suctions air inside the urine tank so that urine will be drawn into the urine tank by a negative pressure therein. The urine receptacle has: a support sheet having no water permeability with a urine drainage port to which the urine drainage tube is connected; a urine absorbing sheet, held by the support sheet, for absorbing urine; a urine absorbing space forming material placed between the support sheet and the urine absorbing sheet; a urine backflow prevention sheet, placed between the urine absorbing sheet and the top sheet, with a plurality of funnel-shaped pores; and, between the top sheet and the urine backflow prevention sheet, there is a urine detection sensor with two rectangular electrodes which become electrically conductive when they come into contact with urine.

FIGS. 1 through 4 are diagrams showing an embodiment of the present invention. FIG. 1 is a diagram of an automatic urine disposal device of the present invention; FIG. 2 is an exploded perspective view of the device with its urine tank partially removed and its lid case removed; FIG. 3 is an exploded and enlarged perspective view of a urine receptacle; and FIG. 4 is an enlarged cross-sectional view of the urine receptacle taken along the line A-A in FIG. 3.

FIGS. 1 through 4 show an example in which a urine pack, which serves as a urine storage container, is housed in the urine tank. Although a urine receptacle 1 is represented as a flat structure in these figures, it is in fact structured such that it is concave like a funnel on the surface that is in contact with the wearer's crotch, and its width at the middle in the longitudinal direction (direction of the wearer's front and rear) is narrower at the middle part, as shown in FIGS. 1 and 3. The urine receptacle 1 is thus shaped like an hourglass so that it fits the wearer's crotch.

The urine receptacle shown in FIG. 1 is a view from the top, looking down at the surface that comes in contact with the wearer's crotch. A urine absorbing sheet 3 for absorbing discharged urine and a urine detection sensor 4 (electrodes 4 a and 4 b) for detecting urination are placed inside the urine receptacle. Below the urine absorbing sheet 3, a bead-shaped urine absorbing space forming material 3 a is placed, as seen in FIG. 4. A set formed of the urine absorbing sheet 3 and the urine absorbing space forming material 3 a is sometimes collectively referred to as a urine collecting member 3.

On the urine receptacle 1, gathers 5 are formed. The gathers 5 have a three-dimensional structure for preventing urine from leaking from the sides. The urine collecting member 3 and the urine detection sensor 4 are structured so as to have a long length in the direction of the wearer's front and rear with his/her crotch at the middle in order to detect and collect discharged urine from a large area. A urine drainage tube 6 is connected to the middle part of the urine collecting member 3. A signal line 7 is connected to the urine detection sensor 4. Also, a urine drainage tube 9 and a signal line 10 are connected to a portable urine disposal device 8, and a joint 11 is connected to one end of the urine drainage tube 9 and it includes a connector that is connected to one end of signal line 10.

The joint 11 is capable of linking the urine drainage tube 6 to the urine drainage tube 9, and the connector therein is capable of connecting the signal line 7 to the signal line 10 through a single operation. After using the urine receptacle 1 for a day, or if it becomes dirty due to defecation, the urine receptacle 1 can be detached from the portable urine disposal device 8 at the joint 11 and discarded so that the wearer can wear a new urine receptacle 1.

As shown in FIG. 3, the urine receptacle 1 consists of a support sheet 12, the urine collecting member 3, a sheet 13 with funnel-shaped pores, the urine detection sensor 4, a cushion sheet 14, and a top sheet 15. The gathers 5 are made of a nonwoven fabric that does not let water pass through. The gathers 5 are shaped and arranged such that they stand along the longitudinal outline of the top sheet 15, tilting toward the inside, and they are glued by a processing method, such as a heat sealing method. The height of the gathers 5 is approximately 15 mm. These tilting gathers 5 prevent urine from leaking from the sides due to movement or weight shift of the wearer.

The support sheet 12 is made of a flexible material, such as a foamed polyethylene sheet. In the urine collecting member 3, consisting of the urine absorbing sheet and the urine absorbing space forming material 3 a, a flow path 3 b is formed, as shown in FIG. 4, and this flow path 3 b serves as a small urine absorbing space for collecting urine. Also, a urine drainage port 12 a is formed on the support sheet 12, and the urine drainage tube 6 passes through this urine drainage port 12 a. The urine drainage tube 6 is made of soft, flexible materials such as soft resins. As seen in FIG. 5, the urine backflow prevention sheet 13 is formed by a polyethylene film with no water permeability and having funnel-shaped pores 18.

The electrodes 4 a and 4 b, constituting the urine detection sensor 4, are glued and arranged such that they are parallel to the long edges of an electrode support sheet 36. The electrode support sheet 36, which has a high water permeability, is formed by a thin thermally bonded nonwoven fabric, and it is placed between the urine backflow prevention sheet 13 and the cushion sheet 14. The cushion sheet 14 also has high water permeability and is formed by a thin thermally bonded nonwoven fabric. The cushion sheet 14 is made flexible so as to improve the comfort for the wearer.

The top sheet 15 is formed by a thin thermally bonded nonwoven fabric having a high water permeability. Since both the top sheet 15 and the cushion sheet 14 have a high water permeability, urine discharged by the wearer can smoothly pass through these sheets and can be detected by the urine detection sensor 4. The cushion sheet 14 has a thickness of 3 to 5 mm to improve the comfort for the wearer and to prevent discharged urine from returning to the skin of the wearer.

The top sheet 15 is designed as a mesh sheet having a thickness of approximately 1 mm to ensure a high water and sweat absorbing rate. By allowing urine to rapidly reach the cushion sheet 14 through small pores in the mesh sheet, the wearer will feel less dampness on his/her skin. The top sheet 15 is fixed so as to cover the cushion sheet 14, the urine detection sensor 4, the urine backflow prevention sheet 13, and the urine collecting member 3, and each side of the top sheet 15 is bonded to the support sheet 12. A processing method, such as a heat sealing method, is used to bond the top sheet 15 to the support sheet 12.

The support sheet has a length of approximately 320 mm (in the direction of the wearer's front and rear), a maximum width of approximately 130 mm, a minimum width of approximately 90 mm, and a thickness of approximately 2 mm. The urine collecting member 3 has a length of approximately 250 mm (direction of the wearer's front and rear), a width of approximately 45 mm, and a thickness of approximately 10 mm. The urine backflow prevention sheet 13 and the cushion sheet 14 both have approximately the same length and width as that of the urine collecting member 3.

The portable urine disposal device 8 consists of a urine tank 35, a lid case 37, and a battery box 38. The urine tank 35 is made of resins and has the shape of a rectangular solid with an opening on the top. A spring 27 is located at each corner of the bottom plate of the urine tank 35 to provide elastic suspension to a support board 26. A urine pack 25, which serves as a urine storage container, is sealed with a sheet of heavy paper like that of a milk carton, and two tube guide holes 24 a and 25 b are formed on a top surface 25 c of the urine pack 25. Although not shown, the urine pack 25 contains particulate superabsorbent polymers, such as cross-link polyacrylic acid soda, that become gelatinized after absorbing urine. The superabsorbent polymers provide a urine swaying motion control means that prohibits urine from swaying (rippling) inside the urine pack 25.

The urine pack 25 is made with, for example, a sheet of heavy paper like that of a milk carton, and is shaped like a rectangular solid. A partition plate (not shown) is placed inside the pack so that the pack can be resistant to vacuum pressure. The capacity of the urine pack 25 is approximately 500 ml, which is sufficient for storing the fluid produced during two instances of urination. As a portable device, however, its dimensions can be adjusted to 110 mm×110 mm×50 mm (605 ml). Also, for longer usage times, such as clinical use or nighttime use, its capacity can be made 1000 ml or more. Note that the shape of the urine tank 35 and the urine pack 25 can be changed in order to fit them to the shape of the wearer's body.

A lid plate 33 is located on the top opening of the urine tank 35, and the lid case 37 is provided so as to cover the lid plate 33. In the space defined by the lid case 37 and the lid plate 33, a vacuum pump 29 is provided. The vacuum pump 29 is driven by a motor 28. One end of a suction tube 32 and an air release tube 31 are linked to the vacuum pump 29. Just as with the urine drainage tubes 6 and 9, the suction tube 32 and the air release tube 31 are formed of soft, flexible materials.

The motor 28 uses a battery placed inside the battery box 38, as shown in FIG. 1, as its driving power source, and it is controlled by the controller mounted on a control board 30. The battery box 38 is installed in the lid case 37 like a cassette so as to supply power to the motor 28, and it uses alkaline cells or secondary batteries. The size of the vacuum pump 29 is small; the diameter is approximately 30 mm or smaller, the length is approximately 70 mm or shorter, and the battery voltage is 5 to 9 V.

On the top surface of the lid case 37, a manual switch 43 for manually driving the motor 28 is provided. When the lid case 37 is fitted to the urine tank 35, a one-touch lock mechanism (not shown) is used to lock them together. On the lid plate 33, a cutout section 41 a for guiding the urine drainage tube 9 and another cutout section 41 b for guiding the suction tube 32 are formed. Both the urine drainage tube 9 and the suction tube 32 have a diameter of approximately 5 mm, and the width of each of the cutout sections 41 a and 41 b is approximately 6 mm.

On the end of the urine drainage tube 9 which passes through the cutout section 41 a, a mounting fixture 23 is attached for fixing the urine drainage tube 9 to the urine pack 25. An insertion hole is formed in the mounting fixture 23 for inserting and holding the urine drainage tube 9, and the mounting fixture 23 fixes the urine drainage tube 9 to the tube guide hole 24 a to connect the urine drainage tube 9 to the urine pack 25 while maintaining the airtightness of the urine pack 25. The mounting fixture 23 has a funnel-like shape and is made of flexible materials made of soft resins, and it can be detached from/attached to the tube guide hole 24 a.

The funnel-shaped mounting fixture 23 has its outer surface and inner surface in the shape of a taper. For example, the mounting fixture 23 has a taper angle of 30 degrees from its axis, the largest diameter of the outer surface taper is 8.0 mm, and the smallest diameter is approximately 6.1 mm. As mentioned earlier, the width of the cutout section 41 a on the lid plate 33 is approximately 6 mm. When the urine drainage tube 9 is guided into the cutout section 41 a, the tube cannot be pulled upwards due to the mounting fixture 23, as seen in FIG. 2.

The mounting fixture 23 is inserted into the tube guide hole 24 a formed on the top surface 25 c of the urine pack 25 from the side with the smallest diameter (6.1 mm), while holding the inserted urine drainage tube 9. The diameter of the tube guide hole 24 a is approximately 6.5 mm, which is somewhere between the largest and smallest diameters of the taper provided on the outer surface of the mounting fixture 23. When the mounting fixture 23 is fixed to the tube guide hole 24 a, the urine pack 25 becomes sealed while maintaining its airtightness. The mounting fixture 23 is fitted to the tube guide hole 24 a by insertion, and it is configured to be detachable from/attachable to the tube guide hole 24 a. The urine drainage tube 9 becomes connected to the urine pack 25 by the mounting fixture 23 becoming fitted to the tube guide hole 24 a.

The suction tube 32 has one end linked to the vacuum pump 29, and a filter 34 is attached on the other end thereof. The filter 34 serves to remove the odor, but it also prevents fluid that may spread in the urine pack 25 at the time of urine suction from being vacuumed into the vacuum pump 29.

A mounting fixture 32 a is attached to the other side of the suction tube 32 to fix the suction tube 32 to the urine pack 25. This mounting fixture 32 a has the same configuration as the mounting fixture 23 which is attached to the urine drainage tube 9. The mounting fixture 32 a is fitted to the tube guide hole 24 b by insertion, and it is configured to be detachable from/attachable to the tube guide hole 24 b. The mounting fixture 24 a becomes fitted to the tube guide hole 24 b while maintaining the airtightness of the urine pack 25.

FIG. 2 shows the urine drainage tube 9 with the mounting fixture 23 attached thereto and the suction tube 32 with the mounting fixture 32 a attached thereto, guided and fitted into the cutout sections 41 a and 41 b, respectively. While maintaining the tubes and the mounting fixtures in state, the lid plate 33 and then the lid case 37 are placed on the top opening of the urine tank 35, as shown in FIG. 1. The ends of the urine drainage tube 9 and suction tube 32 are inserted into the tube guide holes 24 a and 24 b, respectively, which are provided on the urine pack 25. The mounting fixtures 23 and 32 a are pressed down below the cutout sections 41 a and 41 b provided on the lid plate 33, and the taper parts of the fixtures are inserted and glued to the tube guide holes 24 a and 24 b provided on the urine pack 25.

Meanwhile, the urine pack 25 is pressed upward by the support plate 26, which is elastically supported by the springs 27. This mechanism allows an increase in the degree of adhesion between the mounting fixtures 23 and 32 a, on the one hand, and the tube guide holes 24 a and 24 b provided on the urine pack 25, on the other hand. Note that, application of a soft material on the surface 25 c of the urine pack 25 having the tube guide holes 24 a and 24 b can also improve the degree of adhesion between the mounting fixtures 23 and 32 a, and the tube guide holes 24 a and 24 b.

As shown in FIG. 6, the urine detection sensor (electrodes) has a conducting surface 16 and an insulating surface 17, and the signal line 7 is connected to this sensor. The insulating surface 17 side of the electrodes 4 a and 4 b (the urine detection sensor 4) is glued to the electrode support sheet 36. When urine is stored between the electrodes 4 a and 4 b, the surface 16 becomes electrically conductive, and the sensor detects urination. Since the current generated between the electrodes 4 a and 4 b is approximately 0.1 mA and is thus extremely low, the electric current will have no impact on the wearer.

A urine detection signal from the urine detection sensor 4 is sent to a controller mounted on the control board 30 via the signal lines 7 and 10. The insulating surface 17 of the electrode 4 is made of an insulating material, such as paper or vinyl. The conducting surface 16 is created by applying aluminum by an evaporation method to the backside of the insulating surface 17. The urine detection sensor (electrodes) 4 has a length of approximately 200 mm, a width of approximately 5 mm, and a thickness of approximately 0.2 mm. The distance between the electrodes 4 a and 4 b, arranged in parallel with each other, is approximately 30 mm.

As the urine backflow prevention sheet 13, a plurality of minute funnel-shaped pores 18 are formed on a polyethylene film, as seen in FIG. 5, and each pore has a large top area and a small bottom area. Urine discharged onto the top sheet 15 enters a top opening 18 a of the funnel-shaped pore 18 formed in the urine backflow prevention sheet 13, and it gets absorbed by the urine collecting member 3.

Some urine remains uncollected in the flow path 3 b or other space inside the urine collecting member 3 due to surface tension of the urine. If a weight shift caused by the wearer changing his/her posture results in some kind of physical impact being applied to the urine collecting member 3, the residual urine may flow back to the urine detection sensor 4. By making the area of a bottom opening 18 b of the funnel-shaped pore 18 small, it becomes difficult for the urine to flow back. For example, the diameter of the top opening 18 a of each funnel-shaped pore 18 is 1 to 2 mm, the diameter of the bottom opening 18 b of each funnel-shaped pore 18 is 0.5 to 1 mm, and the funnel-shaped pores 18 are arranged with a 3 to 5 mm interval.

Note that, it is desirable that a surface acting agent be applied to or woven into the urine backflow prevention sheet 13 such that surface tension becomes reduced and discharged urine will smoothly flow from the top surface to the bottom surface. Also, pores in the urine backflow prevention sheet 13 can be formed by a perforation method, for example. In performing the perforation method, the sheet 13 is placed between jigs of a pore forming plate and a mesh plate, and hot air is blown at the pore forming plate and is suctioned from the mesh plate side, creating pores.

The urine receptacle 1 as described above is attached to the wearer (not shown) such that it touches his/her urinating part inside their underwear. The portable urine disposal device 8, including the lid case 37 containing the urine tank 35, vacuum pump 29, and motor 28, will be carried around by the wearer, or it is placed on or under the bed when the wearer is lying on a bed.

When the wearer urinates with the device placed in the manner described above, discharged urine flows into the urine detection sensor 4 after passing through the top sheet 15 and the cushion sheet 14. Urine then passes through the urine backflow prevention sheet 13 and becomes absorbed by the urine collecting member 3. When the space between the electrodes 4 a and 4 b of the urine detection sensor 4 is filled with urine, the surface 16 becomes electrically conductive. The urine detection signal from the urine detection sensor 4 is then sent to the controller mounted on the control board 30 via the signal lines 7 and 10.

The controller mounted on the control board 30 activates the motor 28, which drives the vacuum pump 29. When the vacuum pump 29 is activated, the air pressure inside the urine pack 25 becomes lower due to the withdrawal of air therefrom, creating negative pressure in the urine drainage port 12 a of the urine receptacle 1. When negative pressure is created in the urine drainage port 12 a, urine absorbed by the urine collecting member 3 of the urine receptacle 1 is efficiently vacuumed by the urine drainage tube 6 due to suction power generated by the negative pressure. Urine, vacuumed by the urine drainage tube 6 is then drawn by negative pressure into the urine pack 25 via the urine drainage tube 9 and is stored therein.

Note that, upon urinating, the wearer also can use the manual switch 43 to activate the motor 28 to draw the urine into the urine pack 25.

Urine, drawn into the urine pack 25 then undergoes a chemical reaction with particulate super absorbent polymers (not shown) and becomes gelatinized. Gelatinization of the urine can prevent a swaying (rippling) movement of the urine inside the urine pack 25. Therefore, it is possible to configure a portable automatic urine disposal device in a preferred form, in which urine will not leak even if it is carried around.

When urination by the wearer is completed and the urine detection signal from the urine sensor 4 is no longer sent out, the controller mounted on the control board 30 stops the motor 28, which stops the vacuum pump 29. It is also possible to stop the motor 28 and vacuum pump 29 by using the manual switch 43. If the urine pack 25 has sufficient capacity for holding two-times-worth of urine, the next urination process is conducted in the same manner.

After urine is stored in the urine pack 25, the urine pack 25 must be discarded by first unlocking the lock mechanism (not shown) to separate the urine tank 35 and the lid case 37, and then by removing the mounting fixtures 23 and 32 a from the urine pack 25. The urine pack 25 is made of paper, and thus it can be disposed of as burnable waste.

After using the urine receptacle 1 for a day, or if it becomes dirty due to defecation, the urine receptacle 1 must be discarded and replaced with a new urine receptacle 1 by disconnecting the urine drainage tubes 6 and 9, as well as the signal lines 7 and 10, from the one-touch joint 11. The urine receptacle 1 can be disposed of as burnable waste.

From the standpoint of proper hygiene, the urine drainage tube 9 must be replaced after one or two days of use. Replacement of the urine drainage tube 9 can be carried out by disconnecting the urine drainage tubes 6 and 9, as well as the signal lines 7 and 10, from the one-touch joint 11. Then, after separating the urine tank 35 and the lid case 37, the mounting fixture 23 must be removed from the tube guide hole 24 a on the urine pack 25, as shown in FIG. 2. The mounting fixture 23 can be easily removed by grabbing the mounting fixture 23 and pulling it out from the tube guide hole 24 a. Replacement of the urine drainage tube 9 can be performed easily as well as cleanly.

The drainage tube 9 must then be removed from the cutout section 41 a and disposed of with the mounting fixture 23, followed by installation of a new urine drainage tube 9 into the tube guide hole 24 a provided on the urine pack 25. Note that air leakage of the suction tube 32 can be examined in the same manner as replacement of the urine drainage tube 9.

Thus, the urine discharged by the wearer can be disposed of, and backflow of urine to the urine detection sensor 4 can be prevented even if a weight shift by the wearer causes a physical impact on the urine collecting member 3, since the present invention uses the urine backflow prevention sheet 13, which has no water permeability. Although there is the possibility that urine comes in contact with the urine detection sensor 4 through the funnel-shaped pores 18 in the urine backflow prevention sheet 13 provided immediately below the urine detection sensor 4, the sensor will not operate improperly since the bottom surface of the urine detection sensor 4 (the electrodes 4 a and 4 b) is designed as an insulating surface 17.

For such urine disposal as described above, a urine detection sensor with a plurality of funnel-shaped pores is placed on top of the urine backflow sheet (on the top sheet side). Discharged urine can easily flow from the top sheet to the urine absorbing sheet, since each funnel-shaped pore has a large opening area at the top, and discharged urine cannot backflow easily as each funnel-shaped pore has a small opening area at the bottom. This is because the urine on the urine absorbing sheet has a surface tension. Therefore, even though a urine detection sensor with a pair of electrodes is used, it is possible to prevent incorrect operation of the vacuum pump caused by residual urine, and, also, the wearer can use the device comfortably.

Note that, while urine is directed into the urine pack contained inside the urine tank in the embodiment described above, it is clear that it is also possible to seal the urine tank with the lid, form a tube guide hole on the lid, and attach the urine drainage tube to the hole. In this case, the other end of the suction tube can be fixed and linked to the urine tank.

FIGS. 7 through 9 show other examples of the urine detection sensor 4.

FIG. 7 shows the rectangular electrode 4 a glued on one side of the electrode support sheet 36 and the rectangular electrode 4 b glued on the other side of the electrode support sheet 36. The insulating surface 17 of the electrodes 4 a and 4 b is glued onto the electrode support sheet 36. The urine detection sensor 4 shown in FIG. 7 is also capable of correct urine detection.

FIG. 8 shows the rectangular electrode 4 a glued on one side of the electrode support sheet 36 and the rectangular electrode 4 b glued on the other side of the electrode support sheet 36, but, in this example, the electrodes are glued at the same locations with the sheet in between. The insulating surface 17 of the electrodes 4 a and 4 b is glued onto the electrode support sheet 36. The urine detection sensor 4 shown in FIG. 8 is also capable of correct urine detection.

FIG. 9 shows the electrode support sheet 36, with the rectangular electrodes 4 a and 4 b glued thereon, divided into electrode support sheets 36 a and 36 b. The insulating surface 17 of the electrodes 4 a and 4 b is glued onto the electrode support sheets 36 a and 36 b. The urine detection sensor 4 shown in FIG. 9 is also capable of correct urine detection. Also note that incorrect operation of the urine detection sensor 4 can be prevented even if the electrode support sheets 36 a and 36 b contain moisture.

As described above, in accordance with the present invention, a urine detection sensor is placed on (the top sheet side of) a urine backflow prevention sheet having a plurality of funnel-shaped pores. Since this configuration is capable of inhibiting urine from flowing back, it is possible to prevent incorrect operation of a vacuum pump caused by residual urine even though a urine detection sensor having a pair of electrodes is used. Such a configuration will allow the wearer to use the device comfortably.

Therefore, the device of the present invention is capable of preventing incorrect operation of a vacuum pump caused by residual urine even though a urine detection sensor having a pair of electrodes is used and can be comfortably used by its wearer.

The preferred embodiment described herein is therefore illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all variations which come within the meaning of the claims, are intended to be embraced therein. 

1. An automatic urine disposal device, comprising: a urine receptacle for absorbing urine discharged by a wearer, a urine tank for storing urine collected by the urine receptacle, and a urine drainage tube for directing urine from the urine receptacle into the urine tank, characterized in that, a vacuum pump for lowering pressuring inside said urine tank is provided, said urine receptacle has a top sheet to be placed in contact with the wearer, a urine absorbing sheet for absorbing urine that has passed through the top sheet, a urine backflow prevention sheet having a plurality of pores placed between the top sheet and the urine absorbing sheet, and a urine detection sensor with a pair of electrodes placed between said top sheet and said urine backflow prevention sheet, and said urine tank is sealed.
 2. The automatic urine disposal device according to claim 1, characterized in that the plurality of pores formed on said urine backflow prevention sheet are funnel-shaped.
 3. The automatic urine disposal device according to claim 2, characterized in that said urine backflow prevention sheet does not have water permeability, the urine backflow prevention sheet is placed between the top sheet with water permeability and the urine absorbing sheet for absorbing urine, said electrodes are rectangular-shaped and become electrically conductive when in contact with urine, and said vacuum pump becomes activated when said urine detection sensor detects urine and lowers pressure inside said urine tank.
 4. The automatic urine disposal device according to claim 3, characterized in that said top sheet has water permeability, said urine tank houses a sealed urine pack, and a urine swaying motion control means is contained in the urine pack for controlling swaying motions of urine that flows into the urine pack.
 5. The automatic urine disposal device according to claim 1, characterized in that said urine receptacle has a support sheet with a urine drainage port formed thereon, the support sheet having no water permeability, and said urine absorbing sheet is held by this support sheet.
 6. The automatic urine disposal device according to claim 5, characterized in that a urine absorbing space forming material is placed between said support sheet and said urine absorbing sheet.
 7. The automatic urine disposal device according to claim 4, characterized in that said urine drainage tube consists of a first urine drainage tube on the urine pack side and a second urine drainage tube on the urine receptacle side, and a joint for connecting the first and second urine drainage tubes is provided such that the first and second urine drainage tubes can be freely detached from/attached to each other.
 8. The automatic urine disposal device according to claim 3, characterized in that the electrodes of said urine detection sensor are placed between the cushion sheet and said urine backflow prevention sheet.
 9. A urine receptacle for absorbing urine discharged from the urinating part of a wearer, to be used with an automatic urine disposal device, comprising: a support sheet with a urine drainage port formed thereon, the support sheet having no water permeability, a urine absorbing sheet for absorbing urine held by said support sheet, a urine backflow prevention sheet with funnel-shaped pores, the urine backflow prevention sheet being located between said urine absorbing sheet and a top sheet, and a urine detection sensor having two electrodes, the urine detection sensor being placed between said top sheet and said urine backflow prevention sheet.
 10. The urine receptacle according to claim 9, characterized in that a urine absorbing space forming material is placed between said support sheet and said urine absorbing sheet.
 11. The urine receptacle according to claim 10, characterized in that a plurality of funnel-shaped pores are formed on said urine backflow prevention sheet, and said electrodes are rectangular-shaped.
 12. The urine receptacle according to claim 9, characterized in that a cushion sheet is placed between said top sheet and said urine backflow prevention sheet, and said electrodes are placed between the cushion sheet and said urine backflow prevention sheet. 